SYDNEY – Australian police have seized crystal methamphetamine worth more than $1 billion Australian dollars ($712 million), some of it concealed in gel bra inserts, authorities said Monday. It was one of the country’s biggest drug busts.

Three people from Hong Kong and a Chinese national were arrested during the operation which Justice Minister Michael Keenan described as the largest seizure of liquid methamphetamine in Australian history.

“This has resulted in 3.6 million individual hits of ice being taken off our streets with a street value of AU$1.26 billion,” he said, referring to crystal meth by a nickname.

“This largest seizure of liquid methamphetamine to date is the result of organized criminals, targeting the lucrative Australian ice market from offshore.”

Australian Federal Police Commander Chris Sheehan said the joint operation with Chinese authorities began in December 2015 when the Australian Border Force examined a shipping container out of Hong Kong in Sydney. It originated in mainland China.

“That shipping container was found to contain gel bra inserts and hidden inside those gel bra inserts was 190 liters of liquid methamphetamine,” he said.

The seizure was referred to the Australian Federal Police, who began an investigation and traced an additional 530 liters of liquid methamphetamine to five storage units in Sydney, where they were found inside art supplies.

In January, a 33-year-old Hong Kong man was arrested and charged in connection with the original seizure.

A further two Hong Kongers, a man, 37, and a 52-year-old woman, along with a Chinese man, 59, were also arrested and charged with knowingly taking part in the manufacture of a commercial quantity of a prohibited drug over the stash in the storage units.

“We are alleging that the people we have arrested weren’t just mere bit-players, they were significant players within this criminal network,” said Sheehan, adding that they all face life in prison if convicted.

The bust comes two months after Prime Minister Malcolm Turnbull unveiled a AU$300 million strategy to combat the growing use of ice following a government report that Australia had proportionally more users than most countries.

The report showed that the use of the highly addictive drug had doubled since 2007 to more than 200,000 users in 2013, with anecdotal evidence of higher current numbers.

An Australian Crime Commission report published last year found that while $80 bought one gram of ice in China, users in Australia had to pay $500 for the same amount.